Sieve for the sifting of materials



Dec. 14, 1954 E. COTTERILL ETAL 2,696,8 7

SIEVE FOR THE SIFTING OF MATERIALS Filed July 12, 1950 //7 van 20/5 I Ernesf Gaffer/W Ernesz Rob/77500 By fhe/r a/fomeys United States Patent" SIEVE FOR THE SIFTING. OFMATERIALS Ernest Cotterill, Coventry, and ErnestRobinsom- Bocking, Braintree, England, assignors .to Courtaulds' Lir'nited, London, England, a. British company.

ApplicationflulylZ, 1950, Serial No. 173,322

Claimspriority, application Great. Britain September 16,1949

4 Claims. (Cl.'139420) This invention relates to' bolting or sewing cloth and the likewfor the sifting of materials.

A" bolting cloth should have a number of desirable properties including a uniform meshwhich'will be maintained during use, good wear-resistance and durability, and freedom from blocking by the substance being, screened. It is known to use bolting cloth of wire in plain i and :twill weaves and of silk in both plain and leno weaves or combinations of plain and leno weaves. It has been proposed in British patent specification No. 546,075 to produce a bolting cloth made from a thermoplastic artificial thread containing one or more continuous filaments woven in a plain weave in which the threads are prevented from slipping over one another by thermally welding the warp and weft threads at their crossings. It has also been proposed in United States patent specification No. 2,297,729 to produce a screen having resilient spaced single filament strands of a synthetic non-metallic resinous material in which the strands are set in resilient interengagement with each other. It has also been proposed in United States patent specification No. 2,355,635 to produce an open mesh resilient screen of a synthetic linear polyamide condensation product comprising single filament warp and weft strands having permanent crimps in each strand, the alternate crimps being obtuse and com plementarily registering at the strand intersections and intermediate crimps spaced from the intersections.

The object of the present invention is to provide a bolting cloth which has and maintains good uniformity of apertures.

According to the present invention bolting cloth is constructed of monofilaments of synthetic fibre-forming material in 2 X 2 matt weave having a weight in grams per square metre equal to the product of the specific gravity of the synthetic fibre-forming material and a number between 17.5 and 44 and having cover factors for warp and weft directions approximately equal and between the limits of 650 and 1150.

The cover factor is the product of the number of monofilaments per inch in the fabric under consideration (Y) multiplied by the square root of the quotient of the denier (D) and the specific gravity (S) of the synthetic fibreforming material, that is, the cover factor The monofilaments of synthetic fibre-forming material preferably consist of a synthetic linear polyamide made as described in United States patent specification No. 2,130,948, for example the polyamide from hexamethylene diamine and adipic acid. Monofilaments of other synthetic fibre-forming materials may also be used, for example monofilaments of a resin obtained by the copolymerisation of vinyl chloride and vinyl acetate, monofilaments of a resin obtained by the copolymerisation of vinyl chloride and acrylonitrile, monofilaments of polyacrylonitrile or monofilaments of the polyester obtained from ethylene glycol and terephthalic acid.

The accompanying drawing illustrates on an enlarged scale a bolting cloth in accordance with the present invention. In the drawing, warp threads 1, 2 are interwoven with weft threads 3, 4 in a 2 x 2 matt weave. The Warp and weft threads consist of monofilaments of denier of the polyamide from hexamethylene diamine and adipic acid. The cloth is woven with 237 ends per inch and 235 picks per inch to give 118.5 apertures per inch in the warp direction and 117.5 aperturesper inch in the Weft directions The weight ofthe fabrlc is 35.0 grams per square metre. TheLcover factor in the warp direction is and the-cover factor in the weft direction is The cloth shown has apertures '5 of good. uniformity.

Interlockingof the'warp and weft threads attli'eir in-' tersections is notnecessary SlIlCG- durlng use the warp threads 1, Z'and weft threads 3, 4 return after. distortion" of 'the individual threads so that the uniformity ofthe' apertures 5 is maintained. 0

Thebolting cloths constructed in accordance wlth the present inventionican: be used for bolting; screening" and sifting of materials or for textile screen printmg'or other Monofilaments of 20 denier of the polyamide from hexamethylene diamine and adipic acid were Woven in a 2 x 2 matt weave with 214 ends per inch and 214 picks per inch to give 107 apertures in both warp and weft directions. The weight of the fabric was 41.3 grams per square metre. The cover factor in both warp and weft directions was The fabric was used as a bolting cloth and was found to have good uniformity of apertures.

Example 2 Monofilaments of 1S denier of the polyamide from hexamethylene diamine and adipic acid were woven in a 2 x 2 matt weave with 262 ends per inch and 262 picks per inch to give 131 apertures per inch in both warp and weft directions. The weight of the fabric was 37.5 grams per square metre. The cover factor in both Warp and Weft directions was The fabric was used as a bolting cloth and was found to have good uniformity of apertures.

Example 3 The fabric had good uniformity of apertures when used as a bolting cloth.

Example 4 Monofilaments of 15 denier of the copolymer of vinyl chloride and vinyl acetate were woven in a 2 x 2 matt 3 weave with 274 ends per inch and 274 picks per inch to give 137 apertures per linear inch in both warp and weft directions. The weight of the fabric was 40.6 grams per square metre. The cover factor in both warp and weft directions was What we claim is:

1. A sieve for the sifting of materials having a bolting cloth which has and maintains good uniformity of apertures and which consists of monofilaments of synthetic fibre-forming material in 2 x 2 matt weave having a weight in grams per square metre equal to the product of the specific gravity of the synthetic fibre-forming material and a number between 17.5 and 44 and having cover factors for the warp weft directions approximately equal and between the limits of 650 and 1150.

2. A sieve for the sifting of materials having a bolting cloth which has and maintains good uniformity of apertures and which consists of monofilaments of the polyamide from hexamethylene diamine and adipic acid in 2 X 2 matt weave having a weight in grams per square metre equal to the product of the specific gravity of the polyamide and a number between 17.5 and 44 and having cover factors for the Warp and weft directions approximately equal and between the limits of 650 and 1150.

3. A sieve for the sifting of materials having a bolting cloth which has and maintains good uniformity of aper tures and which consists of monofilaments of the polyester from ethylene glycol and terephthalic acid in 2 X 2 matt weave having a weight in grams per square metre equal to the product of the specific gravity of the polyester and a number between 17.5 and 44 and having cover factors for the warp and weft directions approximately equal and between the limits of 650 and 1150.

4. A sieve for the sifting of materials having a bolting cloth which has and maintains good uniformity of apertures and which consists of monofilaments of 15 denier of the polyamide from hexamethylene diamine and adipic acid in a 2 x 2 matt weave with 237 ends per inch and 235 picks per inch, having a weight of 35.0 grams per square metre and cover factors in the warp and weft directions of 860 and 853.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,650,998 Nones Nov. 29, 1927 2,252,554 Carothers Aug. 12, 1941 2,354,435 Stedman July 25, 1944 2,355,635 Dubiiier Aug. 15, 1944 2,364,404 Thomas Dec. 5, 1944 2,551,175 Smith May 1, 1951 

